Pennyroyal

Pennyroyal (Mentha pulegium) is a member of the mint family, a perennial herb. It is a herb useful for its culinary, fragrance, medicinal and decorative uses.^[1]

Pennyroyal has small, oval-shaped leaves in a dark green colour. They are smooth. The leaves have a strong, pungent mint odour.

There is a European pennyroyal and an American pennyroyal.^[1] The differences are minor and can be observed in the flowers (four stamens for the European and two for the American).^[1]

Grow pennyroyal in the herb garden or as a border plant. It can also be grown as groundcover as it tolerates poor soil.^[2] It can become invasive quite quickly, in the manner typical of members of the mint family. Planting in containers or surrounded by polyethylene bags can curb its spread.^[1][2] If planting more than one, plant 25cm or 12 inches apart.

Plant in partial shade to full sun.^[1] Pennyroyal prefers well-drained, rich soil that retains moisture.

It is not prone to many plant diseases.

Pennyroyal oil obtained simply from crushing the leaves and rubbing it on your skin can be useful for deterring insects such as flies, chiggers, ticks, mosquitoes, etc.^[1] (See Caution below for the essential oil.)

Pennyroyal can be added to vinegar for a flavoured vinegar. It can be drunk as a tea.^[1]

Pennyroyal should not be used in large doses by pregnant persons.^[1][2]

Do not use pennyroyal essential oil without being a qualified herbalist who knows its properties and how to apply it. The essential oil is highly toxic and ingestion or application of the oil is dangerous.^[3] Pennyroyal should never be used on pet animals without veterinary advice; it can prove lethal.^[4]